Videos: Joins in and Modifying by Reference in data.table

Click here for a coding vignette on modifying data by reference in data.table
Author

George I. Hagstrom

Published

November 23, 2025

I have uploaded two videos. In the first I go over some slides we didn’t have time for in the initial meetup, covering how to perform joins using data.table. You can watch this video here: extra join slides video

In the second video I go through a coding vignette where I talk about how to modify an object by reference (or in-place) using data.table. This is a key technique for maximizing memory efficiency when working with large data sets. I will also go over deep versus shallow copies.

You can watch the video here: modifying in place

The code I used for this vignette can be found here: data_table_reference_vignette.R

For more information, consider reading the vignette on the data.table page: https://cran.r-project.org/web/packages/data.table/vignettes/datatable-reference-semantics.html, which we follow somewhat.